Pouch compositions are known in the art. These compositions have the advantage that they are easy to dose, handle, transport and store. Recently, water-soluble pouches containing cleaning or fabric care compositions have become popular. Usually the pouches are formed by placing two sheets of film together, sealing three edges, filling with the appropriate product, which is typically a gel or liquid, and then sealing the forth edge.
The film material used in water-soluble pouches is necessarily relatively fragile since it must release the product quickly, completely and without leaving residue. To achieve this, the film material must be thin and must have a high water-reactivity. This can lead to problems with the product being released prematurely due to the stresses of production, packing and transportation or due to exposure to a moist environment. In particular, it is difficult to stop the pouches from leaking small amounts of product, a process which is known as ‘weeping’. A weeping pouch exhibits small quantities of the pouch contents on the film surface. Weeping causes the pouches to feel unpleasant to the touch. In addition, weeping pouches can contaminate the surface of other materials through physical contact.
The incorporation of powder into film material is known in the art. See, for example, JP-A-64/29438 (Kao) which describes a polyvinyl alcohol type film obtained by distributing an aqueous dispersion containing 5-30% by weight of a fine powder with a mean particle size of from 0.5-100 microns on one or both sides and then drying the film. The resultant film is said to have good slip properties and adhesion resistance. In addition, powdering of film material is known. See, for example, EP-A-338350 (Asahi) which describes a dusting treatment agent for imparting inter-film lubricity to a film of thermoplastic resin.
The applicant has surprisingly found that weeping can be reduced or eliminated by coating water-soluble films with powder having a specific oil absorption of 0.4 ml/m2 or more.